1. Field of the Invention
This invention relates to a transformer and a backlight apparatus as well as a display apparatus.
2. Description of the Related Art
A display apparatus is available wherein a liquid crystal panel of the transmission type is illuminated using a backlight apparatus in the past.
The backlight apparatus includes a cold cathode fluorescent lamp and a driving circuit (inverter circuit) which supplies a high frequency voltage higher than 1 kV to the cold cathode fluorescent lamp.
In most cases, the driving circuit includes a transformer (inverter transformer) for generating a high-voltage high-frequency voltage from a dc voltage.
In the past, the driving circuit in most cases has a configuration wherein one transformer is provided for one cold cathode fluorescent lamp. However, another configuration has become frequently adopted wherein a large number of cold cathode fluorescent lamps are driven by a single transformer in order to achieve power saving.
Incidentally, in order to keep the brightness of a plurality of cold cathode fluorescent lamps uniform, it is necessary to supply uniform current to the cold cathode fluorescent lamps. A driving circuit has been proposed which includes a balance transformer or a balance capacitor for suppressing the dispersion of current interposed between a transformer and each of a plurality of cold cathode fluorescent lamps in order to achieve such uniform current. A driving circuit of the type just described is disclosed, for example, in Japanese Patent Laid-Open No. 2006-140055.